This invention relates to photographic filters, and more particularly concerns a filter which will produce accurate color pictures taken in moderately deep sea water.
Underwater photography is enjoying a great rise in popularity. Thousands of recreational and commercial scuba divers, underwater photographers and snorklers have discovered the astonishing life-forms and brilliant colors to be photographed under the surface of the seas.
As these photographers have discovered, however, water acts as a powerful light filter. Uncorrected photographs taken at depths of greater than about 5 feet of seawater are predominantly cyan in cast, and photos taken at depths of about 50 feet may show only varying shades of cyan and grey. Such photographs are not attractive, and they do not represent accurately the colors which are naturally present.
To overcome this color loss, many photographers use photographic flash units. These units are expensive, not always reliable, and limit the photographer to pictures having camera-to-subject distances of less than 8 feet, and preferably less than 4 feet.
An alternate method of overcoming color loss is to use a color correcting filter in conjunction with the camera. Commonly used filters are those known as color correcting 10 red (CC10R) and color correcting 20 red (CC20R). These filters were not originally designed for use in seawater, and provide insignificant, if any, color correction. Pictures taken using these filters have a slightly altered, but still very dominant and unattractive cyan cast.
It is the general object of the present invention to provide a photographic filter for use in underwater photography which permits chromatically correct pictures to be taken at depths of up to 50 feet or more of seawater without flash units or other artificial light sources.
It is another object to provide a filter which will not deteriorate or change optical properties even long after its manufacture, or after extensive use.